The invention relates to a new process for manufacturing liners for vehicle roofs, particularly for roofs with certain integrated functions, such as electrical conducts, lamp soffits, electrical connectors, thin flat speakers, head airbags, etc., this process allowing to quickly and efficiently obtain the linings with an optimal level of performance.
The invention also encompasses a lining for vehicle roofs with integrated functions such as those related above.
As is well known, vehicle roofs incorporate an inner lining which must offer minimum performance, such as being self-supported, being easily and perfectly adaptable to the diverse shapes of vehicle roofs, being lightweight, having good acoustical absorption and thermal insulation properties and a pleasant external look and feel.
In order to fulfill these requirements, the use of multilayer liners is generally resorted to, in which different materials are arranged in thin layers, so that each layer provides its characteristics to the lining, with these layers glued to each other to create the layered element.
A common configuration used consists of a first layer, in contact with the roof, made of a liner material, to which is adhered a second layer consisting of a fiberglass grid or mesh, these layers being joined to each other by glue. Over the fiberglass grid or mesh is placed a substantially thicker central layer, on top of which is another fiberglass grid or mesh, and then a final outer layer which is the visible layer of the lining, this last layer made of a lightweight material. All of the layers which make up the lining, except for the outer or cosmetic layer, support such lining to provide the suitable stiffness and the aforementioned self-supporting property.
More recently, manufacturers of the automobile industry have required from their suppliers not only the roof lining, but also the set formed by said lining and certain functions, such as sun shades, handles, lamp soffits or electrical wiring, with all of these accessories assembled at a later stage of the roof forming in a press. In this sense also known are vehicle linings which have these accessories pre-assembled, so that when the lining is attached to the vehicle roof the above mentioned accessories are automatically installed. A roof of this type is described in Spanish Patent 9301338 belonging to this applicant.
More evolved systems even include an electrical or electronic component for simply and quickly connecting, for example, the power connection required by lighting systems. In this sense we can cite European Patents 0346154 and 0473263, as well as Spanish Patent 8607841.
The process proposed by the invention, and therefore the lining obtained with it, constitutes a novel technological advance in the field as it integrates all the functions required in the lining manufacturing process, where these functions are such as electrical connectors, electronic plates or devices, air conditioning and heating ducts, electrical wiring, flat speakers, head airbags, etc.
With this purpose and more specifically, the process employs a press with two upper fixed positioning mould and a single lower mould with three positions, where the process stages are the following:
At a first position (A) of the lower mould, in which it is not opposite the two upper moulds, the function supporting material is placed on top of it, with the aforementioned lower mould having a suitable profile for defining on said support the recesses which will house such functions.
At a second operative stage the lower mold is placed in position (B) beneath the first fixed upper mold, whose profile is complementary to that of the single lower mold, defining the aforementioned recesses when one mold is placed against the other.
At a third operative stage the lower mold returns to position (A) to receive the functions which are housed in its recesses, and on top of this the layers of different materials which complete the lining with the suitable adhesives when required for their final attachment.
After this the lower mold is sent towards position (C) beneath the second upper mold, and as these two molds are joined the aforementioned complementary layers of the lining adapt their shape to the base support on which the different functions were already set, creating housings for these and completing the lining.
Finally, the lower mold returns to position (A), that is, a position where it is not opposite any of the upper molds, when the finished lining is extracted with the functions set within it.
In accordance with the above exposition the lining must be made in a suitable material for forming the recesses or compartments for the different functions, maintaining stable this deformation after pressing, in order for which the support layer will consist of thermoplastic, thermostable or composite materials.
Returning once again to the process, the possibility exists of using two presses, so that the first press deforms the support body to obtain the recesses for the functions and a second press joins this support to its functions and shapes the rest of the lining layers, as well as the outer coating.
A possible variation of this realisation consists of using two presses with two identical lower molds and two different upper molds, one for shaping the required references and housings for the functions and another to give it its final shape of the roof. Firstly a set of layers is formed, one of card or paper, on it a fiberglass layer and finally a polyurethane layer with an adhesive on its lower face, i.e. between the polyurethane and fiberglass layers.
This first set of layers is introduced in a first press where the required references and the housings for the functions are formed. Afterwards the formed layer set is removed from the press, to later distribute in it the desired functions to be integrated. On top of this set is placed another set formed by the remaining layers and the outer coating, both to be later introduced in a second press which will give the final shape to the lined roof.
By using two different presses there is also the possibility of obtaining in one the support and simultaneously in another the remaining layers of the lining, so that the functions are later coupled to the support and the remaining layers which make up the lining are later joined as a cover of the recesses.